Drop Python 3.10

[dopplershift]

The point is coming to drop Python 3.10, though I'm open to hearing opinions on when exactly that should happen. Official EOL for 3.10 is October 2026. Current and upcoming versions in the community requiring Python 3.11:

• Sphinx 8.2
• Numpy 2.3.0
• SciPy 1.16 (in RC)
• Matplotlib 3.11 (branching soon)

Python 3.14 will be here in October and is another consideration for our CI matrix. Due to the current bug in Dependabot (and our .python-version file saying 3.10) we're not going to get updates for these versions.

I'm inclined to do this somewhat soon since at best our next feature release would be August.

TODO:

• [ ] Update .python-version (unless Dependabot gets fixed)
• [ ] Run pyupgrade --py311-plus
• [ ] Update packaging metadata (e.g. pyproject.toml)
• [ ] Update GHA workflows to remove 3.10 and include 3.11 as needed
• [ ] Update minimum dependency versions as needed to resolve 3.11 environment
• [ ] Grep codebase for \b3\.10\b

[kgoebber]

In light of your comments and thinking about CI matrix, I would concur with your opinion to drop support of Python 3.10 somewhat soon.